[PATCH] IRQ: warning message cleanup
[linux-2.6.git] / kernel / irq / manage.c
1 /*
2  * linux/kernel/irq/manage.c
3  *
4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5  * Copyright (C) 2005-2006 Thomas Gleixner
6  *
7  * This file contains driver APIs to the irq subsystem.
8  */
9
10 #include <linux/irq.h>
11 #include <linux/module.h>
12 #include <linux/random.h>
13 #include <linux/interrupt.h>
14
15 #include "internals.h"
16
17 #ifdef CONFIG_SMP
18
19 /**
20  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
21  *      @irq: interrupt number to wait for
22  *
23  *      This function waits for any pending IRQ handlers for this interrupt
24  *      to complete before returning. If you use this function while
25  *      holding a resource the IRQ handler may need you will deadlock.
26  *
27  *      This function may be called - with care - from IRQ context.
28  */
29 void synchronize_irq(unsigned int irq)
30 {
31         struct irq_desc *desc = irq_desc + irq;
32
33         if (irq >= NR_IRQS)
34                 return;
35
36         while (desc->status & IRQ_INPROGRESS)
37                 cpu_relax();
38 }
39 EXPORT_SYMBOL(synchronize_irq);
40
41 #endif
42
43 /**
44  *      disable_irq_nosync - disable an irq without waiting
45  *      @irq: Interrupt to disable
46  *
47  *      Disable the selected interrupt line.  Disables and Enables are
48  *      nested.
49  *      Unlike disable_irq(), this function does not ensure existing
50  *      instances of the IRQ handler have completed before returning.
51  *
52  *      This function may be called from IRQ context.
53  */
54 void disable_irq_nosync(unsigned int irq)
55 {
56         struct irq_desc *desc = irq_desc + irq;
57         unsigned long flags;
58
59         if (irq >= NR_IRQS)
60                 return;
61
62         spin_lock_irqsave(&desc->lock, flags);
63         if (!desc->depth++) {
64                 desc->status |= IRQ_DISABLED;
65                 desc->chip->disable(irq);
66         }
67         spin_unlock_irqrestore(&desc->lock, flags);
68 }
69 EXPORT_SYMBOL(disable_irq_nosync);
70
71 /**
72  *      disable_irq - disable an irq and wait for completion
73  *      @irq: Interrupt to disable
74  *
75  *      Disable the selected interrupt line.  Enables and Disables are
76  *      nested.
77  *      This function waits for any pending IRQ handlers for this interrupt
78  *      to complete before returning. If you use this function while
79  *      holding a resource the IRQ handler may need you will deadlock.
80  *
81  *      This function may be called - with care - from IRQ context.
82  */
83 void disable_irq(unsigned int irq)
84 {
85         struct irq_desc *desc = irq_desc + irq;
86
87         if (irq >= NR_IRQS)
88                 return;
89
90         disable_irq_nosync(irq);
91         if (desc->action)
92                 synchronize_irq(irq);
93 }
94 EXPORT_SYMBOL(disable_irq);
95
96 /**
97  *      enable_irq - enable handling of an irq
98  *      @irq: Interrupt to enable
99  *
100  *      Undoes the effect of one call to disable_irq().  If this
101  *      matches the last disable, processing of interrupts on this
102  *      IRQ line is re-enabled.
103  *
104  *      This function may be called from IRQ context.
105  */
106 void enable_irq(unsigned int irq)
107 {
108         struct irq_desc *desc = irq_desc + irq;
109         unsigned long flags;
110
111         if (irq >= NR_IRQS)
112                 return;
113
114         spin_lock_irqsave(&desc->lock, flags);
115         switch (desc->depth) {
116         case 0:
117                 printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
118                 WARN_ON(1);
119                 break;
120         case 1: {
121                 unsigned int status = desc->status & ~IRQ_DISABLED;
122
123                 /* Prevent probing on this irq: */
124                 desc->status = status | IRQ_NOPROBE;
125                 check_irq_resend(desc, irq);
126                 /* fall-through */
127         }
128         default:
129                 desc->depth--;
130         }
131         spin_unlock_irqrestore(&desc->lock, flags);
132 }
133 EXPORT_SYMBOL(enable_irq);
134
135 /**
136  *      set_irq_wake - control irq power management wakeup
137  *      @irq:   interrupt to control
138  *      @on:    enable/disable power management wakeup
139  *
140  *      Enable/disable power management wakeup mode
141  */
142 int set_irq_wake(unsigned int irq, unsigned int on)
143 {
144         struct irq_desc *desc = irq_desc + irq;
145         unsigned long flags;
146         int ret = -ENXIO;
147
148         spin_lock_irqsave(&desc->lock, flags);
149         if (desc->chip->set_wake)
150                 ret = desc->chip->set_wake(irq, on);
151         spin_unlock_irqrestore(&desc->lock, flags);
152         return ret;
153 }
154 EXPORT_SYMBOL(set_irq_wake);
155
156 /*
157  * Internal function that tells the architecture code whether a
158  * particular irq has been exclusively allocated or is available
159  * for driver use.
160  */
161 int can_request_irq(unsigned int irq, unsigned long irqflags)
162 {
163         struct irqaction *action;
164
165         if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
166                 return 0;
167
168         action = irq_desc[irq].action;
169         if (action)
170                 if (irqflags & action->flags & SA_SHIRQ)
171                         action = NULL;
172
173         return !action;
174 }
175
176 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
177 {
178         /*
179          * If the architecture still has not overriden
180          * the flow handler then zap the default. This
181          * should catch incorrect flow-type setting.
182          */
183         if (desc->handle_irq == &handle_bad_irq)
184                 desc->handle_irq = NULL;
185 }
186
187 /*
188  * Internal function to register an irqaction - typically used to
189  * allocate special interrupts that are part of the architecture.
190  */
191 int setup_irq(unsigned int irq, struct irqaction *new)
192 {
193         struct irq_desc *desc = irq_desc + irq;
194         struct irqaction *old, **p;
195         unsigned long flags;
196         int shared = 0;
197
198         if (irq >= NR_IRQS)
199                 return -EINVAL;
200
201         if (desc->chip == &no_irq_chip)
202                 return -ENOSYS;
203         /*
204          * Some drivers like serial.c use request_irq() heavily,
205          * so we have to be careful not to interfere with a
206          * running system.
207          */
208         if (new->flags & SA_SAMPLE_RANDOM) {
209                 /*
210                  * This function might sleep, we want to call it first,
211                  * outside of the atomic block.
212                  * Yes, this might clear the entropy pool if the wrong
213                  * driver is attempted to be loaded, without actually
214                  * installing a new handler, but is this really a problem,
215                  * only the sysadmin is able to do this.
216                  */
217                 rand_initialize_irq(irq);
218         }
219
220         /*
221          * The following block of code has to be executed atomically
222          */
223         spin_lock_irqsave(&desc->lock, flags);
224         p = &desc->action;
225         old = *p;
226         if (old) {
227                 /*
228                  * Can't share interrupts unless both agree to and are
229                  * the same type (level, edge, polarity). So both flag
230                  * fields must have SA_SHIRQ set and the bits which
231                  * set the trigger type must match.
232                  */
233                 if (!((old->flags & new->flags) & SA_SHIRQ) ||
234                     ((old->flags ^ new->flags) & SA_TRIGGER_MASK))
235                         goto mismatch;
236
237 #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
238                 /* All handlers must agree on per-cpuness */
239                 if ((old->flags & SA_PERCPU_IRQ) !=
240                     (new->flags & SA_PERCPU_IRQ))
241                         goto mismatch;
242 #endif
243
244                 /* add new interrupt at end of irq queue */
245                 do {
246                         p = &old->next;
247                         old = *p;
248                 } while (old);
249                 shared = 1;
250         }
251
252         *p = new;
253 #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
254         if (new->flags & SA_PERCPU_IRQ)
255                 desc->status |= IRQ_PER_CPU;
256 #endif
257         if (!shared) {
258                 irq_chip_set_defaults(desc->chip);
259
260                 /* Setup the type (level, edge polarity) if configured: */
261                 if (new->flags & SA_TRIGGER_MASK) {
262                         if (desc->chip && desc->chip->set_type)
263                                 desc->chip->set_type(irq,
264                                                 new->flags & SA_TRIGGER_MASK);
265                         else
266                                 /*
267                                  * SA_TRIGGER_* but the PIC does not support
268                                  * multiple flow-types?
269                                  */
270                                 printk(KERN_WARNING "No SA_TRIGGER set_type "
271                                        "function for IRQ %d (%s)\n", irq,
272                                        desc->chip ? desc->chip->name :
273                                        "unknown");
274                 } else
275                         compat_irq_chip_set_default_handler(desc);
276
277                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
278                                   IRQ_INPROGRESS);
279
280                 if (!(desc->status & IRQ_NOAUTOEN)) {
281                         desc->depth = 0;
282                         desc->status &= ~IRQ_DISABLED;
283                         if (desc->chip->startup)
284                                 desc->chip->startup(irq);
285                         else
286                                 desc->chip->enable(irq);
287                 } else
288                         /* Undo nested disables: */
289                         desc->depth = 1;
290         }
291         spin_unlock_irqrestore(&desc->lock, flags);
292
293         new->irq = irq;
294         register_irq_proc(irq);
295         new->dir = NULL;
296         register_handler_proc(irq, new);
297
298         return 0;
299
300 mismatch:
301         spin_unlock_irqrestore(&desc->lock, flags);
302         if (!(new->flags & SA_PROBEIRQ)) {
303                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
304                 dump_stack();
305         }
306         return -EBUSY;
307 }
308
309 /**
310  *      free_irq - free an interrupt
311  *      @irq: Interrupt line to free
312  *      @dev_id: Device identity to free
313  *
314  *      Remove an interrupt handler. The handler is removed and if the
315  *      interrupt line is no longer in use by any driver it is disabled.
316  *      On a shared IRQ the caller must ensure the interrupt is disabled
317  *      on the card it drives before calling this function. The function
318  *      does not return until any executing interrupts for this IRQ
319  *      have completed.
320  *
321  *      This function must not be called from interrupt context.
322  */
323 void free_irq(unsigned int irq, void *dev_id)
324 {
325         struct irq_desc *desc;
326         struct irqaction **p;
327         unsigned long flags;
328
329         WARN_ON(in_interrupt());
330         if (irq >= NR_IRQS)
331                 return;
332
333         desc = irq_desc + irq;
334         spin_lock_irqsave(&desc->lock, flags);
335         p = &desc->action;
336         for (;;) {
337                 struct irqaction *action = *p;
338
339                 if (action) {
340                         struct irqaction **pp = p;
341
342                         p = &action->next;
343                         if (action->dev_id != dev_id)
344                                 continue;
345
346                         /* Found it - now remove it from the list of entries */
347                         *pp = action->next;
348
349                         /* Currently used only by UML, might disappear one day.*/
350 #ifdef CONFIG_IRQ_RELEASE_METHOD
351                         if (desc->chip->release)
352                                 desc->chip->release(irq, dev_id);
353 #endif
354
355                         if (!desc->action) {
356                                 desc->status |= IRQ_DISABLED;
357                                 if (desc->chip->shutdown)
358                                         desc->chip->shutdown(irq);
359                                 else
360                                         desc->chip->disable(irq);
361                         }
362                         spin_unlock_irqrestore(&desc->lock, flags);
363                         unregister_handler_proc(irq, action);
364
365                         /* Make sure it's not being used on another CPU */
366                         synchronize_irq(irq);
367                         kfree(action);
368                         return;
369                 }
370                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
371                 spin_unlock_irqrestore(&desc->lock, flags);
372                 return;
373         }
374 }
375 EXPORT_SYMBOL(free_irq);
376
377 /**
378  *      request_irq - allocate an interrupt line
379  *      @irq: Interrupt line to allocate
380  *      @handler: Function to be called when the IRQ occurs
381  *      @irqflags: Interrupt type flags
382  *      @devname: An ascii name for the claiming device
383  *      @dev_id: A cookie passed back to the handler function
384  *
385  *      This call allocates interrupt resources and enables the
386  *      interrupt line and IRQ handling. From the point this
387  *      call is made your handler function may be invoked. Since
388  *      your handler function must clear any interrupt the board
389  *      raises, you must take care both to initialise your hardware
390  *      and to set up the interrupt handler in the right order.
391  *
392  *      Dev_id must be globally unique. Normally the address of the
393  *      device data structure is used as the cookie. Since the handler
394  *      receives this value it makes sense to use it.
395  *
396  *      If your interrupt is shared you must pass a non NULL dev_id
397  *      as this is required when freeing the interrupt.
398  *
399  *      Flags:
400  *
401  *      SA_SHIRQ                Interrupt is shared
402  *      SA_INTERRUPT            Disable local interrupts while processing
403  *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
404  *
405  */
406 int request_irq(unsigned int irq,
407                 irqreturn_t (*handler)(int, void *, struct pt_regs *),
408                 unsigned long irqflags, const char *devname, void *dev_id)
409 {
410         struct irqaction *action;
411         int retval;
412
413         /*
414          * Sanity-check: shared interrupts must pass in a real dev-ID,
415          * otherwise we'll have trouble later trying to figure out
416          * which interrupt is which (messes up the interrupt freeing
417          * logic etc).
418          */
419         if ((irqflags & SA_SHIRQ) && !dev_id)
420                 return -EINVAL;
421         if (irq >= NR_IRQS)
422                 return -EINVAL;
423         if (irq_desc[irq].status & IRQ_NOREQUEST)
424                 return -EINVAL;
425         if (!handler)
426                 return -EINVAL;
427
428         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
429         if (!action)
430                 return -ENOMEM;
431
432         action->handler = handler;
433         action->flags = irqflags;
434         cpus_clear(action->mask);
435         action->name = devname;
436         action->next = NULL;
437         action->dev_id = dev_id;
438
439         select_smp_affinity(irq);
440
441         retval = setup_irq(irq, action);
442         if (retval)
443                 kfree(action);
444
445         return retval;
446 }
447 EXPORT_SYMBOL(request_irq);
448